Business day
Business day means the intraday period of time starting at the business hour of 8:15 a.m. and ending at the business hour of 4:45 p.m., on all days except Saturdays, Sundays, and any holiday on which a derivatives clearing organization and its domestic financial markets are closed, including a Federal holiday in the United States, as established under 5 U.S.C. 6103.
Source
17 CFR § 39.2
Scoping language
For the purposes of this part: